Vanadium-based frit materials, and/or methods of making the same

ABSTRACT

Certain example embodiments relate to improved seals for glass articles. Certain example embodiments relate to a composition used for sealing an insulted glass unit. In certain example embodiments the composition includes vanadium oxide, barium oxide, zinc oxide, and at least one additional additive. For instance, another additive that is a different metal oxide or different metal chloride may be provided. In certain example embodiments, a vacuum insulated glass unit includes first and second glass substrates that are sealed together with a seal that includes the above-described composition.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part of U.S. application Ser. No.12/929,875, filed Feb. 22, 2011 now U.S. Pat. No. 8,802,203, the entirecontents of which are hereby incorporated by reference.

FIELD OF THE INVENTION

Certain example embodiments of this invention relate to improved fitmaterials for glass articles (e.g., for use in vacuum insulated glass orVIG units), and/or methods of making the same, as well as articlesincluding such improved fit materials and/or methods of making the same.More particularly, certain example embodiments relate to vanadium-basedfrit materials having a reduced melting point, and/or methods of makingthe same. In certain example embodiments, the improved insulated sealsare used in connection with vacuum insulated glass (VIG) units, and/or amethod is provided for sealing VIG units with the improved seals.

BACKGROUND AND SUMMARY OF EXAMPLE EMBODIMENTS OF THE INVENTION

Vacuum IG units are known in the art. For example, see U.S. Pat. Nos.5,664,395, 5,657,607, and 5,902,652, the disclosures of which are allhereby incorporated herein by reference.

FIGS. 1-2 illustrate a conventional vacuum IG unit (vacuum IG unit orVIG unit). Vacuum IG unit 1 includes two spaced apart glass substrates 2and 3, which enclose an evacuated or low pressure space 6 there between.Glass sheets/substrates 2 and 3 are interconnected by peripheral or edgeseal of fused solder glass 4 and an array of support pillars or spacers5.

Pump out tube 8 is hermetically sealed by solder glass 9 to an apertureor hole 10 which passes from an interior surface of glass sheet 2 to thebottom of recess 11 in the exterior face of sheet 2. A vacuum isattached to pump out tube 8 so that the interior cavity betweensubstrates 2 and 3 can be evacuated to create a low pressure area orspace 6. After evacuation, tube 8 is melted to seal the vacuum. Recess11 retains sealed tube 8. Optionally, a chemical getter 12 may beincluded within recess 13.

Conventional vacuum IG units, with their fused solder glass peripheralseals 4, have been manufactured as follows. Glass frit in a solution(ultimately to form solder glass edge seal 4) is initially depositedaround the periphery of substrate 2. The other substrate 3 is broughtdown over top of substrate 2 so as to sandwich spacers 5 and the glassfrit/solution there between. The entire assembly including sheets 2, 3,the spacers, and the seal material is then heated to a temperature ofapproximately 500° C., at which point the glass frit melts, wets thesurfaces of the glass sheets 2, 3, and ultimately forms hermeticperipheral or edge seal 4. This approximately 500° C. temperature ismaintained for from about one to eight hours. After formation of theperipheral/edge seal 4 and the seal around tube 8, the assembly iscooled to room temperature. It is noted that column 2 of U.S. Pat. No.5,664,395 states that a conventional vacuum IG processing temperature isapproximately 500° C. for one hour. Inventors Lenzen, Turner and Collinsof the '395 patent have stated that “the edge seal process is currentlyquite slow: typically the temperature of the sample is increased at 200°C. per hour, and held for one hour at a constant value ranging from 430°C. and 530° C. depending on the solder glass composition.” Afterformation of edge seal 4, a vacuum is drawn via the tube to form lowpressure space 6.

The composition of conventional edge seals are known in the art. See,for example, U.S. Pat. Nos. 3,837,866; 4,256,495; 4,743,302; 5,051,381;5,188,990; 5,336,644; 5,534,469; 7,425,518, and U.S. Publication No.2005/0233885, the disclosures of which are all hereby incorporatedherein by reference.

Unfortunately, the aforesaid high temperatures and long heating times ofthe entire assembly utilized in the formulation of edge seal 4 areundesirable. This is especially the case when it is desired to use aheat strengthened or tempered glass substrate(s) 2, 3 in the vacuum IGunit. As shown in FIGS. 3-4, tempered glass loses temper strength uponexposure to high temperatures as a function of heating time. Moreover,such high processing temperatures may adversely affect certain low-Ecoating(s) that may be applied to one or both of the glass substrates incertain instances.

FIG. 3 is a graph illustrating how fully thermally tempered plate glassloses original temper upon exposure to different temperatures fordifferent periods of time, where the original center tension stress is3,200 MU per inch. The x-axis in FIG. 3 is exponentially representativeof time in hours (from 1 to 1,000 hours), while the y-axis is indicativeof the percentage of original temper strength remaining after heatexposure. FIG. 4 is a graph similar to FIG. 3, except that the x-axis inFIG. 4 extends from zero to one hour exponentially.

Seven different curves are illustrated in FIG. 3, each indicative of adifferent temperature exposure in degrees Fahrenheit (° F.). Thedifferent curves/lines are 400° F. (across the top of the FIG. 3 graph),500° F., 600° F., 700° F., 800° F., 900° F., and 950° F. (the bottomcurve of the FIG. 3 graph). A temperature of 900° F. is equivalent toapproximately 482° C., which is within the range utilized for formingthe aforesaid conventional solder glass peripheral seal 4 in FIGS. 1-2.Thus, attention is drawn to the 900° F. curve in FIG. 3, labeled byreference number 18. As shown, only 20% of the original temper strengthremains after one hour at this temperature (900° F. or 482° C.). Such asignificant loss (i.e., 80% loss) of temper strength may be undesirable.

As seen in FIGS. 3-4, the percentage of remaining tempering strengthvaries based on the temperature that is exposed to the tempered glass.For example, at 900° F. only about 20% of the original temper strengthremains. When the temperature that the sheet is exposed to is reduced to800° F., about 428° C., the amount of strength remaining is about 70%.Finally, a reduction in temperature to about 600° F., about 315° C.,results in about 95% of the original temper strength of the sheetremaining. As will be appreciated, it is desirable to reduce any temperstrength losses as a result of exposing a tempered sheet of glass tohigh temperatures.

As noted above, the creation of VIG units includes the creation of ahermetic seal that can withstand the pressure applied from the vacuumcreated on inside of the unit. As also discussed above, the creation ofthe seal may conventionally involve temperatures of at or above 500° C.These temperatures are required in order to obtain a high enoughtemperature in order for the frit material used for the seal to melt andform the required seal for the VIG units. As shown above, such atemperature can result in a strength reduction for VIG units usingtempered glass.

One conventional solution to sealing glass substrates together is to usean epoxy. However, in the case of VIG units, epoxy compositions may beinsufficient to hold a seal on a vacuum. Furthermore, epoxies may besusceptible to environmental factors that may further reduce theireffectiveness when applied to VIG units.

Another conventional solution is to use a frit solution that containslead. As is known, lead has a relatively low melting point. Accordingly,temperatures for sealing the VIG units may not need to be as high forother frit materials, and thus the tempering strength of tempered glasssubstrates may not be reduced by the same amount required for other fritbased materials. However, while lead based frits may resolve the abovestructural issues, the usage of lead in the frit may create newproblems. Specifically, the health consequences to the population forproducts that contain lead. Additionally, certain countries (e.g., inthe European Union) may impose strict requirements on the amount of leadthat can be contained in a given product. Indeed, some countries (orcustomers) may require products that are completely lead-free.

Thus, it will be appreciated that techniques for creating improved sealsfor glass articles are continuously sought after. It also will beappreciated that there exists a need in the art for improved seals andthe like that can be integrated with tempered glass units, such as, forexample, VIG units. The seals may be designed to allow for reducedtemperature sealing such that annealed or tempered glass can be sealedwithout detrimental impact on the properties of the glass.

In certain example embodiments, a frit material may provide glass tofrit bonding sufficient for VIG purposes (e.g., in terms of structuralstrength). In certain example embodiments, the provided frit may provideproper glass wetting properties. In certain example embodiments, thefrit may seal and have structural strength and a homogenous glassystructure to provide an adequate barrier to prevent vacuum degradationin example VIG units over a period of time.

In certain instances, improvements in melt flow may enable improved fritmatching to glass expansion and/or increase process tolerances to fritbead variations. Improved wetting and bonding properties of a fritmaterial may increase VIG yield by reducing bonding failures of the fritto the glass. A reduction in crystallization may additionally oralternatively facilitate a selected composition to meeting differentheating environments (e.g., an internal seal, an external seal, etc).

In certain example embodiments, a frit material having a composition isprovided. The frit material may include vanadium oxide between about 50%and 60% weight, barium oxide between about 27% and 33% weight, and zincoxide between about 9% and 12% weight. In certain example embodiments,the frit material may also include at least one additive selected fromamong: Ta₂O₅, Ti₂O₃, SrCl₂, GeO₂, CuO, AgO, Nb₂O₅, B₂O₃, MgO, SiO₂,TeO₂, Tl₂O₃, Y₂O₃, SnF2, SnO2, CuCl, SnCl₂, CeO₂, AgCl, In₂O₃, SnO, SrO,MgO, MoO₃, CsCO₃, CuCl₂, and Al₂O₃.

In certain example embodiments, a vacuum insulted glass (VIG) unit isprovided. The VIG unit may include first and second substantiallyparallel, spaced apart glass substrates. An edge seal is provided arounda periphery of the first and second substrates to form a hermetic sealthere between and at least partially defining a gap between the firstand second substrates. The gap defined between the first and secondsubstrates is at a pressure less than atmospheric. The edge sealincludes a frit material, e.g., as made from a base composition asdescribed herein.

In certain example embodiments, a method of making a frit material isprovided. A base composition is provided to a holder. The basecomposition includes vanadium oxide between about 50% and 60% weight,barium oxide between about 27% and 33% weight, zinc oxide between about9% and 12% weight, and at least one additive selected from among: Ta₂O₅,Ti₂O₃, SrCl₂, GeO₂, CuO, AgO, Nb₂O₅, B₂O₃, MgO, SiO₂, TeO2, Tl2O3, Y2O3,SnF2, SnO₂, CuCl, SnCl2, CeO2, AgCl, In2O3, SnO, SrO, MgO, MoO₃, CsCO₃,CuCl₂, and Al₂O₃. The base composition is melted. The base compositionis cooled or allowed to cool, forming an intermediate glass article. Theintermediate glass article is ground to make the frit material.

In certain example embodiments, a method of making a vacuum insulatedglass (VIG) unit is provided. First and second glass substrates insubstantially parallel, spaced apart relation to one another areprovided. The first and second glass substrates using a frit materialare sealed together, with a gap being defined between the first andsecond substrates. The sealing being performed by melting the fritmaterial at a temperature of no more than about 400 degrees C. Where thefrit material has been formed from a base composition including vanadiumoxide between about 50% and 60% weight, barium oxide between about 27%and 33% weight, zinc oxide between about 9% and 12% weight, and at leastone oxide or chloride-base additive.

In certain example embodiments, a frit material having a composition isprovided. The fit material may include vanadium oxide between about 50%and 60% weight (40-55% molar, more preferably 45-50% molar), bariumoxide (e.g., barium carbonate that converts in whole or in part to BaO)between about 23% and 33% weight (15-35% molar, more preferably 20-23%molar), and zinc oxide between about 9% and 12% weight (15-25% molar,more preferably 19-22% molar). The frit material includes at least afirst and second additive selected from among SnCl₂, CuCl₂, MoO₃, TeO₂,Ta₂O₅, Nb₂O₅, Al₂O₃, SiO₂, and CsCO₃.

Certain example embodiments may include at least two additives. Forexample SnCl2 and SiO2. Certain example embodiments may include three orfour additives selected from among SiO₂, SnCl₂, Al₂O₃, and TeO₂, Certainexample embodiments may use between 5 and 10 different additives thatare selected from among: SnCl₂, CuCl₂, MoO₃, TeO₂, Ta₂O₅, Nb₂O₅, Al₂O₃,SiO₃, and CsCO₃.

The features, aspects, advantages, and example embodiments describedherein may be combined in any suitable combination or sub-combination torealize yet further embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features and advantages may be better and morecompletely understood by reference to the following detailed descriptionof exemplary illustrative embodiments in conjunction with the drawings,of which:

FIG. 1 is a cross-sectional view of a conventional vacuum IG unit;

FIG. 2 is a top plan view of the bottom substrate, edge seal, andspacers of the FIG. 1 vacuum IG unit taken along the section lineillustrated in FIG. 1;

FIG. 3 is a graph correlating time (hours) versus percent temperingstrength remaining, illustrating the loss of original temper strengthfor a thermally tempered sheet of glass after exposure to differenttemperatures for different periods of time;

FIG. 4 is a graph correlating time versus percent tempering strengthremaining similar to that of FIG. 3, except that a smaller time periodis provided on the x-axis;

FIG. 5 is cross-sectional view of a vacuum insulated glass unitaccording to certain example embodiments;

FIG. 6 is a flowchart illustrating a process for making a vacuuminsulated glass unit with a fit material according to certain exampleembodiments;

FIGS. 7A-7D are graphs summarizing properties of compositions accordingto certain example embodiments;

FIGS. 8A-8C are graphs summarizing the quality of compositions accordingto certain exemplary embodiments;

FIG. 9 is a graph showing results when additional elements are added tocompositions according to certain example embodiments;

FIGS. 10A-10C show graphs summarizing impacts of additives being addedto vanadium based fits according to certain example embodiments;

FIGS. 11A-11C show graphs summarizing absorption in the visible andinfrared wavelengths for vanadium based frits according to certainexample embodiments; and

FIGS. 12A-12C are graphs summarizing flow characteristics of examplefrit materials according to certain example embodiments.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS OF THE INVENTION

The following description is provided in relation to several exampleembodiments which may share common characteristics, features, etc. It isto be understood that one or more features of any one embodiment may becombinable with one or more features of other embodiments. In addition,single features or a combination of features may constitute anadditional embodiment(s).

Certain example embodiments may relate to glass units (e.g., VIG units)that include two glass substrates sealed with an improved seal, e.g., ofor including a vanadium-based frit material. In certain exampleembodiments an improved seal may include the following materials:vanadium oxide, barium oxide, and zinc oxide. In addition, certainexample embodiments may include one or more of the following compounds:Ta₂O₅, Ti₂O₃, SrCl₂, GeO₂, CuO, AgO, Nb₂O₅, B₂O₃, MgO, SiO₂, TeO2,Tl2O3, Y2O3, SnF2, SnO₂, CuCl, SnCl2, CeO2, AgCl, In2O3, SnO, SrO, MgO,MoO₃, CsCO₃, CuCl₂, and Al₂O₃.

FIG. 5 is cross-sectional view of a vacuum insulated glass unitaccording to certain example embodiments. VIG unit 500 may include firstand second glass substrates 502 a and 502 b that are spaced apart anddefine a space therebetween. The glass substrates 502 a and 502 b may beconnected via an improved seal 504, of or including a vanadium-basedfrit. Support pillars 506 may help maintain the first and secondsubstrates 502 a and 502 b in substantially parallel spaced apartrelation to one another. It will be appreciated that the CTE of theimproved seal 504 and the glass substrates 502 a and 502 b maysubstantially match one another. This may be advantageous in terms ofreducing the likelihood of the glass cracking, etc. Although FIG. 5 isdescribed in relation to a VIG unit, it will be appreciated that theimproved seal 504, of or including a vanadium-based fit may be used inconnection with other articles and/or arrangements including, forexample, insulating glass (IG) units and/or other articles.

FIG. 6 is a flowchart illustrating a process for preparing a fritmaterial to be used in making a vacuum insulated glass unit according tocertain example embodiments. In step 600, base compounds are combinedand disposed into an appropriate container (e.g., a heat resistantcontainer such as, for example, a ceramic container). In step 602, thecombined compound is melted. Preferably, the temperature to melt thecombined material may be at least 1000° C. In certain exemplaryembodiments, the combined compound is melted at 1000° C. for between 30to 60 minutes. In certain exemplary embodiments, the combined compoundis melted at 1100° C. for 60 minutes. In certain exemplary embodiments,the combined compound is melted at 1200° C. for 60 minutes. In certainexemplary embodiments, the melting temperature is a cycle that includes500° C. for 15 minutes, 550° C. for 15 minutes, 600° C. for 15 minutes,and a ramp up to 1000° C. for 60 minutes.

After the combined compounds are melted, the material may be cooled instep 604, e.g., to form a glass sheet. After cooling, the glass may becrushed or ground into fine particulates in step 606. In certain exampleembodiments, the size of the particulates may be no larger than about100 mesh. Once the glass is ground into a powder, it may be disposedbetween the substrates in step 608. In certain example embodiments, thepowder may be dispensed as a paste with a binder. Heat may then beapplied in step 610 to the glass substrate and the powder. In certainexample embodiments, the heat may be between 300° C. and 400° C., ormore preferably between 325° C. and 375° C. It will be appreciated thatwhen heat of the above temperatures is applied to tempered glass thatthe tempered glass may lose a reduced amount of strength versus whenheat of in excess of 350° C. is applied to the tempered glass. Thus,certain example embodiments preferably involve a frit meltingtemperature of less than 500° C., more preferably less than 425° C., andsometimes less than 350° C.

In certain example embodiments, the combined compounds include thefollowing materials: vanadium oxide, barium oxide, and zinc oxide.

FIGS. 7A-7D show graphs summarizing properties of compositions accordingto certain example embodiments.

The table below corresponds to the data shown in FIG. 7A with thosecompositions with a melt quality of less than 4 (on a scale of 0 to 5)omitted from the table.

TABLE 1 Normalized Moles of Batch Composition V₂O₅ BaO ZnO BaO/ZnO Bi₂O₃B₂O₃ Tg (C.) Tx1 (C.) Rating 43.66% 9.87% 46.47% 0.21 320 410 4 39.01%13.25% 37.37% .35 2.18% 8.20% 312 430 4 47.33% 12.96% 24.41% 0.53 9.95%5.53% 305 380 4 50.24% 23.38% 21.39% 1.33 320 425 4 51.54% 26.26% 16.46%1.60 5.75% 320 410 4.5

The melts shown in FIG. 7A were applied to a microscope glass slide witha temperature of 375° C. applied for 15 minutes. FIG. 7B shows a graphthat includes the crystallization temperature (first crystallizationpeak—Tx1—of the above table) of the above melts. According to certainexemplary embodiments, a preferred temperature for Tx1 may be betweenabout 375° C. and 425° C., preferably about 400° C.

FIG. 7C shows the transition glass temperatures, Tg, compared the abovemelts. The graph showing exemplary data shows that Tg values betweenabout 290 C and 335 C may be preferred for the above compositions.

FIG. 7D includes the above melts in a graph showing the melt qualityversus the barium/zinc ratio.

FIGS. 8A-8C show graphs that summarize the quality of compositionsaccording to certain exemplary embodiments. FIG. 8A summarizes the V₂O₅percentage used in certain exemplary compositions. FIG. 8B summarizesthe BaO percentage used in certain exemplary compositions. FIG. 8Csummarizes the ZnO percentage used in certain exemplary compositions. Asshown in the illustrative graphs, a vanadium percentage of between about51% and 53% may be preferable according to certain example embodiments.

Below, tables 2A-2C show exemplary compositions according to certainexample embodiments. Additionally, examples 7-15 in the tablescorrespond to graphs 8A-8C. For the compositions shown in the belowtables, BaCO₃ factor of 1.287027979 was used to convert to a BaOresulting compound.

TABLE 2A Weights of Batch Weight Composition Normalized WeightPercentage Weight for 25 grams Percentage Ex. V₂O₅ BaO ZnO Normal V₂O₅BaO ZnO V₂O₅ BaO ZnO 1 60 30 10 0.23 13.800 8.880 2.300 55.24 35.55 9.212 52.5 25 10 0.27 14.175 8.687 2.700 55.45 33.99 10.56 3 45 20 10 0.3113.950 7.980 3.100 55.73 31.88 12.39 4 45 10 20 0.32 14.400 4.118 6.40057.79 16.53 25.68 5 52.5 10 25 0.28 14.700 3.604 7.000 58.09 14.24 27.666 60 10 30 0.25 15.000 3.218 7.500 58.33 12.51 29.16 7 52.5 25 10 0.2412.600 7.722 2.400 55.45 33.99 10.56 8 57.5 25 10 0.25 14.375 8.0442.500 57.69 32.28 10.03 9 47.5 25 10 0.28 13.300 9.009 2.800 52.97 35.8811.15 10 52.5 27.5 10 0.26 13.650 9.202 2.600 53.63 36.15 10.22 11 57.527.5 10 0.25 14.375 8.848 2.500 55.88 34.40 9.72 12 47.5 27.5 10 0.2712.825 9.556 2.700 51.13 38.10 10.77 13 52.5 22.5 10 0.28 14.700 8.1082.800 57.40 31.66 10.93 14 57.5 22.5 10 0.26 14.950 7.529 2.600 59.6130.02 10.37 15 47.5 22.5 10 0.29 13.775 8.398 2.900 54.94 33.49 11.57

TABLE 2B Moles of Batch Normalized Moles Glass Ex. V₂O₅ BaO ZnO V₂O₅ BaOZnO Type 1 0.3037 0.1801 0.1132 50.87% 30.17% 18.95% amor- phous 20.3049 0.1722 0.1298 50.24% 28.38% 21.39% glassy 3 0.3064 0.1616 0.152249.41% 26.05% 24.54% amor- phous 4 0.3177 0.0838 0.3156 44.31% 11.68%44.01% amor- phous 5 0.3194 0.0722 0.3400 43.66% 9.87% 46.47% amor-phous 6 0.3207 0.0634 0.3584 43.19% 8.54% 48.27% amor- phous 7 0.30490.1722 0.1298 50.24% 28.38% 21.39% glassy 8 0.3172 0.1636 0.1233 52.51%27.08% 20.41% glassy 9 0.2912 0.1818 0.1370 47.74% 29.80% 22.46% glassy10 0.2949 0.1832 0.1255 48.85% 30.35% 20.80% glassy 11 0.3073 0.17430.1194 51.12% 29.00% 19.87% glassy 12 0.2811 0.1931 0.1323 46.35% 31.83%21.81% glassy 13 0.3156 0.1604 0.1344 51.70% 26.28% 22.01% glassy 140.3278 0.1521 0.1274 53.97% 25.05% 20.98% glassy 15 0.3021 0.1697 0.142149.20% 27.65% 23.15% glassy

The rating shown in Table 2C is based off of deposing the groundcomposition on a microscope glass slide and heating the composition atabout 375° C. for between 10 and 30 minutes.

TABLE 2C Example Tg (C.°) Tx2 (C.°) Tx2 (C.°) Tx1 − Tg Rating 1 280 330540 50 0.0 2 320 425 525 105 4.0 3 280 430 550 150 0.0 4 280 320 365 400.0 5 320 410 560 90 4.0 6 285 425 560 140 0.0 7 315 390 530 75 4.5 8295, 325 415 535 90 5.0 9 320 420 525 100 4.5 10 325 410 540 85 4.5 11315 395 530 80 4.5 12 330 415 560 85 4.0 13 315 400 530 85 5.0 14 305395 530 90 4.0 15 320 395 525 75 4.5

FIG. 9 shows a graph with results of adding additional elements (e.g.,Bi₂O₃ and B₂O₃) to a vanadium based frit. Corresponding data shown inFIG. 9 is also displayed below in Table 3.

TABLE 3 Ex. V2O5 BaO ZnO Bi2O3 B2O3 Tg (C.) Tx1 (C.) DSC Responses 165.39% 14.87% 12.46% 0.00% 7.28% 320 430 medium weak 2 60.96% 13.86%11.61% 0.00% 13.57% 240 415 very weak 3 69.71% 15.85% 13.28% 1.16% 0.00%315 405 strong peaks 4 64.69% 14.71% 12.32% 1.08% 7.20% 325 440 veryweak 5 68.91% 15.67% 13.13% 2.29% 0.00% 320 410 medium weak 6 64.00%14.56% 12.19% 2.13% 7.12% 320 425 very weak 7 59.74% 13.59% 11.38% 1.99%13.30% 315 410 very weak 8 60.34% 13.72% 11.49% 1.00% 13.43% 315 400very weak 9 70.53% 16.04% 13.43% 0.00% 0.00% 315 380 strong peaks

In certain example embodiments, a strong DSC response may correspond toa good remelt quality. In certain example embodiments, the addition ofbismuth in concentrations of between about 0% and 3% may result inincreased remelt flow quality.

In certain example embodiments, a fit that includes V₂O₅, BaO, and ZnOmay further include one or more additives. In certain exampleembodiments, the additives may be between about 0.5% and 15% weight.According to certain example embodiments, the additives may be added toa base composition that includes between about 50% and 60% weight V₂O₅,27% and 33% weight BaO, and 9% and 12% weight ZnO.

Below, Tables 4A-4D show results of including additives to the basecomposition of V₂O₅, BaO, and ZnO. Table 4D shows the melt quality on ascale of about 0 to 5 for each of the compositions. FIGS. 10A-10C showgraphs corresponding to the data shown in the below tables. A BaCO3factor of 1.2870 was used to form the BaO used for the followingexamples.

TABLE 4A Weights (gm) Normalized Weights Ex V2O5 BaO ZnO Additive TypeAmount V2O5 BaO ZnO Additive 1 52.5 22.5 10 TeO2 2 14.175 7.819 2.7000.540 2 52.5 22.5 10 TeO2 4 13.650 7.529 2.600 1.040 3 52.5 22.5 10Ta2O5 5 13.650 7.529 2.600 1.300 4 52.5 22.5 10 Ta2O5 10 13.125 7.2402.500 2.500 5 52.5 22.5 10 Ti2O3 5 13.650 7.529 2.600 1.300 6 52.5 22.510 Ti2O3 10 13.125 7.240 2.500 2.500 7 52.5 22.5 10 SrCl2 2 14.175 7.8192.700 0.540 8 52.5 22.5 10 SrCl2 4 13.650 7.529 2.600 1.040 9 52.5 22.510 GeO2 1 14.175 7.819 2.700 0.270 10 52.5 22.5 10 GeO2 2 14.175 7.8192.700 0.540 11 52.5 22.5 10 CuO 1 14.175 7.819 2.700 0.270 12 52.5 22.510 CuO 2 14.175 7.819 2.700 0.540 13 52.5 22.5 10 AgO 1.5 14.175 7.8192.700 0.405 14 52.5 22.5 10 AgO 3 14.175 7.819 2.700 0.810 15 52.5 22.510 Nb2O5 3 14.175 7.819 2.700 0.810 16 52.5 22.5 10 Nb2O5 6 13.650 7.5292.600 1.560 17 52.5 22.5 10 B2O3 .8 14.175 7.819 2.700 0.216 18 52.522.5 10 B2O3 1.6 14.175 7.819 2.700 0.432

TABLE 4B Normalized Weight Percentage Moles of Batch Addi- CompositionEx V2O5 BaO ZnO tive V2O5 BaO ZnO Additive 1 56.17 30.99 10.70 2.140.309 0.157 0.131 0.013 2 55.00 30.34 10.48 4.19 0.302 0.154 0.129 0.0263 54.43 30.02 10.37 5.18 0.299 0.152 0.127 0.012 4 51.75 28.54 9.86 9.860.285 0.145 0.121 0.022 5 54.43 30.02 10.37 5.18 0.299 0.152 0.127 0.0116 51.75 28.54 9.86 9.86 0.285 0.145 0.121 0.022 7 56.17 30.99 10.70 2.140.309 0.157 0.131 0.013 8 55.00 30.34 10.48 4.19 0.302 0.154 0.129 0.0269 56.78 31.32 10.82 1.08 0.312 0.159 0.133 0.010 10 56.17 30.99 10.702.14 0.309 0.157 0.131 0.020 11 56.78 31.32 10.82 1.08 0.312 0.159 0.1330.014 12 56.17 30.99 10.70 2.14 0.309 0.157 0.131 0.027 13 56.48 31.1510.76 1.61 0.311 0.158 0.132 0.013 14 55.58 30.66 10.59 3.18 0.306 0.1550.130 0.026 15 55.58 30.66 10.59 3.18 0.306 0.155 0.130 0.012 16 53.8729.71 10.26 6.16 0.296 0.151 0.126 0.023 17 56.91 31.39 10.84 0.87 0.3130.159 0.133 0.012 18 56.42 31.12 10.75 1.72 0.310 0.158 0.132 0.025

TABLE 4C Normalized Moles Ex V2O5 BaO ZnO Additive Tg (C.) (Tx1 (C.) Tx2(C.) Tx1 − Tg 1 50.57% 25.71% 21.53% 2.20% 315 400 525 85 2 49.48%25.16% 21.07% 4.30% 315 420 530 105 3 50.68% 25.76% 21.58% 1.99% 320 450130 4 49.69% 25.26% 21.16% 3.90% 320 450 530 130 5 50.71% 25.78% 21.59%1.92% 305 390 495 85 6 49.75% 25.29% 21.18% 3.77% 295 390 470 95 750.56% 25.70% 21.53% 2.21% 315 405 530 90 8 49.47% 25.15% 21.06% 4.32%315 400 530 85 9 50.83% 25.84% 21.64% 1.68% 315 395 530 80 10 49.99%25.41% 21.28% 3.31% 315 400 530 85 11 50.56% 25.71% 21.53% 2.20% 315 385525 70 12 49.47% 25.15% 21.06% 4.31% 320 395 545 75 13 50.61% 25.73%21.55% 2.12% 305 390 525 85 14 49.55% 25.19% 21.10% 4.16% 300 380 80 1550.68% 25.76% 21.58% 1.98% 315 425 550 110 16 49.69% 25.26% 21.16% 3.89%325 440 465 115 17 50.66% 25.75% 21.57% 2.02% 315 410 540 95 18 49.66%25.25% 21.14% 3.95% 320 405 545 85

TABLE 4D Melt Quality @ Melt Quality Example 375 C., 15 min at 350 C.,15 min 1 5.0 4.0 2 4.5 4.0 3 4.5 2.0 4 5.0 2.0 5 4.5 4.5 6 5.0 5.0 75.5+ 5.0 8 5.0 4.5 9 4.5 4.5 10 4.5 4.5 11 4.5 2.0 12 4.0 2.0 13 4.0 5.014 3.5 4.0 15 4.5 2.0 16 5.0 2.0 17 4.0 4.5 18 3.5 2.0

In certain example embodiments, the molar composition of an additive toa base composition higher than is shown in tables 4A-4D. Table 5A showsadditives with an increased additive amount (on a % mole basis). Thebase composition used with the additive amount may be based on, forexample, the base composition shown in Row 1 of Tables 4A-4D. Theadditives shown in Table 5, in the selected quantities displayed, mayimprove melt quality when compared to the above base composition. A melttype of Glassy indicates that a “button” of the compound melted onto aglass plate, forming a homogenous glassy structure. Sinter indicatesthat the compound (in a powder form) fused together, but remained in apowder form.

TABLE 5 Additive Melt Type (350 C. Adhesion to glass Example Type Amountfor 20 minutes) substrate. 1 CuCl 4.00% Glassy No Stick 2 SnCl2 3.99%Glassy No Stick 3 SnCl2 5.99% Glassy, Slight Flow Slight stick 4 SiO26.02% More Glassy No Stick 5 Al2O3 6.00% Glassy No Stick 6 CeO2 4.00%Sinter No Stick 7 TeO2 3.99% Glassy Slight stick 8 TeO2 6.01% GlassySlight stick 9 Tl2O3 3.99% Glassy, Slight Flow No Stick 10 Tl2O3 6.01%Glassy, Slight Flow No Stick

Accordingly, in certain example embodiments, additives of a relativelyincreased amount (e.g., versus those shown in FIG. 4) may be added to abase composition. In certain example embodiments, the additives mayinclude, for example, CuCl, SnCl₂, SiO₂, Al₂O₃, and TeO₂. It will beappreciated that toxic nature of thallium oxide (Tl₂O₃) may preclude itsuse in certain instances.

In certain example embodiments, two or more additives may be included ina base compound. Table 6 shows the results of adding two additives to anexemplary base composition. Table 6 includes example melts at 375 and350. Additionally, 13 mm buttons of the exemplary compounds were testedon a glass plate. The structural strength of the resulting exemplarycompound are also shown in the far right column.

TABLE 6 Melt Melt 13 mm Quality Quality Button Amount 1 Amount 2 (375 C.(350 C. 350 C. Ex Add 1 Add 2 (Mole %) (Mole %) 15-20 Min) 15-20 Min) 20Min Strength 1 TeO2 Al2O3 3.01 3.01 4.5 5.5 glassy Fractures 2 TeO2Al2O3 2.99 5.01 5 4 glassy Fractures 3 TeO2 Al2O3 4.02 3.01 6 5.5 glassyFractures 4 TeO2 Al2O3 3.99 5.00 5 4.5 glassy Fractures 5 TeO2 Al2O35.01 2.99 4.5 4.5 glassy Fractures 6 TeO2 Al2O3 5.00 5.00 5 4.5 glassyFractures 7 TeO2 SiO₂ 3.01 3.00 5 5.5 glassy Fractures 8 TeO2 SiO₂ 2.995.02 5 4.5 glassy Fractures 9 TeO2 SiO₂ 4.00 2.99 5 4 glassy Fractures10 TeO2 SiO₂ 3.99 4.99 5 4.5 Less Fractures glassy 11 TeO2 SiO₂ 5.002.99 4.5 4.5 Less Hard glassy 12 TeO2 SiO₂ 5.00 4.99 4.5 4.5 Less Hardglassy 13 SnCl2 Al2O3 3.01 3.01 5 6 more Hard glassy 14 SnCl2 Al2O3 3.005.01 5 5.5 glassy Hard 15 SnCl2 Al2O3 4.01 3.01 4.5 6 glassy Hard 16SnCl2 Al2O3 4.00 4.99 5.5 6 glassy Hard 17 SnCl2 Al2O3 5.00 2.99 5.5 5.5glassy Fractures 18 SnCl2 Al2O3 5.00 5.00 5.5 5.5 more Hard glassy 19SnCl2 SiO2 3.00 3.00 4.5 4.5 glassy Hard 20 SnCl2 SiO2 3.00 4.99 5 6glassy Hard 21 SnCl2 SiO2 4.00 2.99 6 6 glassy Fractures 22 SnCl2 SiO24.01 4.99 5.5 5.5 glassy Fractures 23 SnCl2 SiO2 5.00 2.99 5 5.5 glassyHard 24 SnCl2 SiO2 5.00 4.99 5.5 5.5 glassy Fractures 25 Al2O3 SiO2 3.013.00 4.5 4 less Hard glassy 26 Al2O3 SiO2 2.99 4.99 5 5.5 less Hardglassy 27 Al2O3 SiO2 4.00 2.99 4.5 4.5 less Hard glassy 28 Al2O3 SiO24.00 4.99 5 4.5 less Hard glassy 29 Al2O3 SiO2 5.01 2.99 5 4.5 less Hardglassy 30 Al2O3 SiO2 5.01 4.99 4 2 less Hard glassy

Accordingly, certain example may include two additives similar to thosefound in examples 3, 16, and 21 as shown in Table 6 (e.g., TeO2 withSiO2, SnCl2 with Al2O3, and SnCl2 with SiO2). In certain exampleembodiments, the addition of two or more additives may have beneficialresults on an exemplary base composition. For example the addition ofSiO2 to another additive may increase the strength of the overall frit.Alternatively, or in addition, TeO2 combined with other additives mayincrease the melt flow and glass wetting qualities of the frit whencompared to a base frit.

In certain example embodiments, the combination of SnCl2 with SiO2and/or Al2O3 may result in an increase in structural strength for theresulting frit material.

In certain example embodiments, one or more additives may be added to abase composition where the amount is between 1% and 10% by weight orbetween about 1% and 6% normalized moles for a batch. In certain exampleembodiments, additives may be added in a smaller amount, for examplebetween about 0.1% and 1% by weight. In certain example embodiments abatch for a base composition (in grams) may include V₂O₅ at 52.5, BaO at22.5, ZnO at 10. In certain example embodiments, additives added to theabove base composition may include: 1) TeO2 at 3.85 gm and Al2O3 at 1.84gm; 2) SnCl2 at 4.65 gm and Al2O3 at 3.12 gm; 3) SnCl2 at 4.55 gm andSiO2 at 1.08 gm. Correspondingly, the additives may then have anormalize weight percentage of: 1) TeO2 at 1.00 and Al2O3 at 0.48; 2)SnCl2 at 1.21 and Al2O3 at 0.81; 3) SnCl2 at 1.18 and SiO2 at 0.28.These examples may correspond to examples 3, 16, and 21 in the abovetable 6.

FIGS. 11A-11C show graphs illustrating absorption in the visible andinfrared wavelengths for vanadium based frits according to certainexample embodiments. As shown in the graphs, example vanadium basedfrits may have absorption of at least 90% across a substantial breath ofthe visible and IR spectrum. In certain example embodiments theabsorption may be about 95%. As discussed in co-pending application Ser.No. 12/929,874, filed on Feb. 22, 2011, entitled “IMPROVED FRITMATERIALS AND/OR METHOD OF MAKING VACUUM INSULATING GLASS UNITSINCLUDING THE SAME”, the entire contents of which are incorporatedherein by reference, frit materials with high visible/IR absorption maybe advantageous.

FIG. 11A shows the absorption properties of a vanadium based frit withTeO₂ and Al₂O₃ used as additives (e.g., Ex. 3 of Table 6). FIG. 11Bshows the absorption properties of a vanadium based frit with SnCl₂ andAl₂O₃ used as additives (e.g., Ex. 16 of Table 6). FIG. 11C shows theabsorption properties of a vanadium based fit with SnCl₂ and SiO₂ usedas additives (e.g., Ex. 21 of Table 6).

In certain example embodiments, the application of IR energy to a fritmaterial may be based on a heating profile where the IR energy appliedto the frit varies over time. Exemplary heating profiles may be found inco-pending application Ser. No. 12/929,874, the entire contents of whichare incorporated herein by reference.

In certain example embodiments, a base composition may be augmented by 3or 4 additives. For example, a batch for a base composition (in grams)may include V₂O₅ at 52.5, BaO at 22.5, ZnO at 10. Accordingly, threeand/or more additives from among TeO2, SnCl2, Al2O3, and SiO2 may beselected to augment the base composition. The ranges (in grams) for theadditives may vary between 0 to 7.5 grams per additive. Thus, on anormalized molar percentage the above additives may be included atbetween 0% and 6%. Thus, the normalized molar percentage of a basecomposition may be V₂O₅ at between about 43% and 50%, BaO between about22% and 26%, ZnO between about 18% and 22%. In certain exampleembodiments, additives (on a normalized molar basis) of TeO2 at around2%, SnCl2 around 2%, Al2O3 around 2%, and SiO2 around 4% may be added tothe base composition.

The techniques, compositions, etc disclosed herein may be used othermethods and/or systems for forming a VIG unit. For example, a vanadiumbased fit may be used to form an edge seal of a VIG unit. Systems,apparatuses, and/or methods used for creating a VIG unit may bedescribed in co-pending application Ser. No. 12/929,876, filed on Feb.22, 2011, entitled “LOCALIZED HEATING TECHNIQUES INCORPORATING TUNABLEINFRARED ELEMENT(S) FOR VACUUM INSULATING GLASS UNITS, AND/ORAPPARATUSES FOR THE SAME”, the entire contents of which are herebyincorporated by reference.

Certain example embodiments may include three or more additives to abase composition that includes vanadium pentaoxide; barium carbonatethat coverts in whole or in part to barium oxide; and zinc oxide. Theabove three “base” frit elements may be included at 35-55% molar forV₂O₅, 15-35% for BaO, and 15-25% molar for ZnO or, more preferably,40-50% molar for V₂O₅, 20-30% for BaO, and 18-22% molar for ZnO.

Along with an example base frit composition, one or more additives maybe added. The additives may include, for example:

-   1) SnCl₂ at between 1-10% molar, which may help reduce glass    softening temperatures and/or reduce crystallization in certain    example embodiments;-   2) CuCl₂ at between 1-5% molar, which may help reduce glass    softening temperature in certain example embodiments;-   3) MoO₃ at between 1-6% molar, which may help reduce glass softening    temperatures in certain example embodiments;-   4) TeO₂ at between 1-10% molar, which may help increase glass flow    ability and/or wetting to a substrate glass in certain example    embodiments;-   5) Ta₂O₅ at between 0.5-5% molar, which may help increase softening    temperature and/or increase crystallization temperature in certain    example embodiments;-   6) Nb₂O₅ at between 0.5-6% molar, which may help increase softening    temperature and/or increase crystallization temperature in certain    example embodiments;-   7) Al₂O₃ at between 0.5-5% molar, which may help increase softening,    weathering ability, chemical durability, and/or mechanical strength    in certain example embodiments;-   8) SiO₂ at between 0.5-5% molar, which may help increase softening,    weathering ability, chemical durability, and/or mechanical strength    in certain example embodiments; and-   9) CsCO₃ at between 0.5-4% molar, which may help increase melt flow    and/or reduce wetting ability in certain example embodiments.

In certain example embodiments, four or more additives, more preferablysix or more additives may be added to the above base composition. Itwill be appreciated that as the number of the additives increases, theinteractions between the various additives may produce different resultsbased on the relative weighting of one or more additives (or the basecomposition). It also will be appreciated that the increased number ofadditives may create synergistic effects (e.g., in terms of glasssoftening temperature, flowability, and/or other adjustments) thatotherwise might not be observable.

In certain example embodiments, one or more additives may be introducedthrough the frit creation process rather than being expresslyintroduced. For example, additive ingredients may be introduced into afrit material as a result of firing the frit material in a crucible. Forinstance, some ingredients may be “leached” from the crucible and intothe frit material. In certain example embodiments, Al₂O₃ and SiO₂ may beleached by this process.

Tables 7-10 show example frit compositions according to certain exampleembodiments. The different tables each include one or more additivesthat are varied while the other ingredients are kept substantially thesame between the example compounds of the give table.

In tables 7A-7C, molybdenum oxide is varied between the examplecompounds; in tables 8A-8C tellurium oxide is varied between the examplecompounds; in tables 9A-9C cesium carbonate is varied between theexample compounds; and in tables 10A-10D tantalum oxide and niobiumoxide are varied between the example compounds.

Tables 7A, 8A, 9A, and 10A show the example frit compositions bynormalized weight percentage. Tables 7B, 8B, 9B, and 10B show theexample fit compositions by normalized mole percent. The values given intables 7-10A and B are normalized to approximately 100% for showncompositions. For example, V₂O₅ from example 1 in table 7A is 54.88% byweight of the fit composition for the fit composition. Similarly, V₂O₅for the same example fit composition is shown as 49.76% mole of theresulting frit composition (e.g., from Table 7B). Thus, the normalizedweight and mole percentages may add up to about 100% for the example fitcompositions shown in the various tables herein. Tables 7C, 8C, 9C, 10C,and 10D show exemplary results for the example frit compositions. As canbe seen in the results of the above noted tables (e.g., tables 7-10),performance of one or more of the above examples may be improved over abase frit material, or a frit material with only one additive asdiscussed above. For example, example fit materials 9 and 11 shown inTable 8 show good flow at 375 degrees C. (5 and 6.5, respectively).

TABLE 7A MoO₃ Examples Normalized Weight Percentage Example V₂O₅ BaO ZnOMoO₃ TeO₂ Ta₂O₅ Al₂O₃ SiO₂ Nb₂O₅ 1 54.88 26.61 10.45 0.87 4.15 1.38 0.000.00 1.65 2 54.64 26.49 10.41 1.31 4.13 1.37 0.00 0.00 1.64 3 54.3926.38 10.36 1.75 4.11 1.37 0.00 0.00 1.64 4 54.15 26.26 10.31 2.19 4.101.36 0.00 0.00 1.63 5 53.91 26.14 10.27 2.63 4.08 1.36 0.00 0.00 1.62 653.67 26.02 10.22 3.07 4.06 1.35 0.00 0.00 1.62

TABLE 7B MoO₃ Examples Normalized Moles of Batch Composition Ex. V₂O₅BaO ZnO MoO₃ TeO₂ Ta₂O₅ Al₂O₃ SiO₂ Nb₂O₅ 1 49.76% 22.24% 21.18% 0.99%4.29% 0.51% 0.00% 0.00% 1.02% 2 49.50% 22.12% 21.08% 1.50% 4.27% 0.51%0.00% 0.00% 1.02% 3 49.25% 22.01% 20.97% 2.00% 4.24% 0.51% 0.00% 0.00%1.01% 4 49.00% 21.90% 20.86% 2.50% 4.22% 0.51% 0.00% 0.00% 1.01% 548.75% 21.79% 20.75% 3.00% 4.20% 0.50% 0.00% 0.00% 1.00% 6 48.50% 21.67%20.65% 3.50% 4.18% 0.50% 0.00% 0.00% 1.00%

TABLE 7C MoO₃ Examples Test Results 375 C. 400 C. Slides Slides 13 mm 13mm 350 C. 375 C. button button Ex. 15 min 15 min 20 min Results 20 minResults 1 5.0 5.5 12.39 glass 13.76 light haze 2 3.0 4.5 12.80 glass14.06 light haze 3 4.0 5.5 12.51 glass 14.14 light haze 4 4.5 5.0 13.08glass 14.22 light haze 5 5.5 5.0 12.93 glass 14.26 light haze 6 5.5 5.512.88 glass 14.50 light haze

TABLE 8A TeO₂ Examples Normalized Weight Percentage Example V₂O₅ BaO ZnOMoO₃ TeO₂ Ta₂O₅ Al₂O₃ SiO₂ Nb₂O₅ 7 54.84 26.59 10.45 2.67 2.42 1.38 0.000.00 1.65 8 54.56 26.46 10.39 2.66 2.91 1.37 0.00 0.00 1.64 9 54.2926.33 10.34 2.65 3.39 1.37 0.00 0.00 1.63 10 54.02 26.19 10.29 2.63 3.881.36 0.00 0.00 1.63 11 53.74 26.06 10.24 2.62 4.37 1.35 0.00 0.00 1.6212 53.47 25.93 10.18 2.61 4.86 1.34 0.00 0.00 1.61 13 53.20 25.80 10.132.59 5.34 1.34 0.00 0.00 1.60 14 52.92 25.66 10.08 2.58 5.83 1.33 0.000.00 1.59

TABLE 8B TeO₂ Examples Normalized Moles of Batch Composition Ex. V₂O₅BaO ZnO MoO₃ TeO₂ Ta₂O₅ Al₂O₃ SiO₂ Nb₂O₅ 7 49.61% 22.17% 21.12% 3.06%2.50% 0.51% 0.00% 0.00% 1.02% 8 49.36% 22.06% 21.01% 3.04% 3.00% 0.51%0.00% 0.00% 1.02% 9 49.11% 21.95% 20.91% 3.03% 3.50% 0.51% 0.00% 0.00%1.01% 10 48.85% 21.83% 20.80% 3.01% 4.00% 0.51% 0.00% 0.00% 1.01% 1148.59% 21.72% 20.69% 2.99% 4.50% 0.50% 0.00% 0.00% 1.00% 12 48.34%21.60% 20.58% 2.98% 5.00% 0.50% 0.00% 0.00% 1.00% 13 48.09% 21.49%20.47% 2.96% 5.50% 0.50% 0.00% 0.00% 0.99% 14 47.83% 21.38% 20.36% 2.95%6.00% 0.49% 0.00% 0.00% 0.98%

TABLE 8C TeO₂ Examples Test Results 375 C. 400 C. Slides Slides 13 mm 13mm 350 C. 375 C. button button Ex. 15 min 15 min 20 min Results 20 minResults 7 5.5 6.0 12.89 glass 14.37 haze 8 3.0 6.5 13.08 glass 14.63light haze 9 3.0 5.0 13.38 glass 14.93 light haze 10 6.5 5.0 13.17 glass14.66 light haze 11 4.5 6.5 13.04 glass 14.72 glass 12 6.0 6.5 12.72glass 14.53 light haze 13 5.5 5.0 12.94 glass 14.59 light haze 14 5.56.0 13.24 glass 14.92 light haze

TABLE 9A CsCO₃ Examples Normalized Weight Percentage Example V₂O₅ BaOZnO MoO₃ TeO₂ Ta₂O₅ Al₂O₃ SiO₂ Nb₂O₅ CsCO₃ 15 52.95 25.68 10.09 2.584.31 1.33 0.00 0.00 1.59 1.47 16 52.69 25.55 10.04 2.57 4.29 1.32 0.000.00 1.59 1.97 17 52.43 25.43 9.99 2.56 4.26 1.32 0.00 0.00 1.58 2.44 1852.17 25.30 9.94 2.54 4.24 1.31 0.00 0.00 1.57 2.92 19 51.91 25.17 9.892.53 4.22 1.31 0.00 0.00 1.56 3.41 20 51.65 25.05 9.84 2.52 4.20 1.300.00 0.00 1.55 3.89

TABLE 9B CsCO₃ Examples Normalized Moles of Batch Composition (%) Ex.V₂O₅ BaO ZnO MoO₃ TeO₂ Ta₂O₅ Al₂O₃ SiO₂ Nb₂O₅ CsCO₃ 15 48.23 21.55 20.532.97 4.47 0.50 0.00 0.00 0.99 0.75 16 48.11 21.50 20.48 2.96 4.46 0.500.00 0.00 0.99 1.00 17 47.99 21.45 20.43 2.96 4.45 0.50 0.00 0.00 0.991.25 18 47.87 21.39 20.38 2.95 4.44 0.50 0.00 0.00 0.99 1.50 19 47.7421.34 20.33 2.94 4.43 0.49 0.00 0.00 0.98 1.75 20 47.62 21.28 20.27 2.934.41 0.49 0.00 0.00 0.98 2.00

TABLE 9C CsCO₃ Examples Test Results 13 mm 13 mm Slide Slide button -button - 350 C. - 375 C. - 375 C. 400 C. Ex. 15 min 15 min 20 minResults 20 min Results 15 5.5 6.5 13.40 glass 14.88 haze 16 5.5 5.513.05 glass 15.40 glass 17 4.0 6.5 13.60 glass 15.17 light haze 18 4.56.5 13.33 glass 14.81 haze 19 6.0 4.5 13.28 glass 14.59 haze 20 4.5 7.013.97 glass 16.36 light haze

TABLE 10A Ta₂O₅ and Nb₂O₅ Examples Normalized Weight Percentage ExampleV₂O₅ BaO ZnO MoO₃ TeO₂ Ta₂O₅ Al₂O₃ SiO₂ Nb₂O₅ 21 53.87 26.12 10.26 2.633.37 1.34 0.00 0.00 2.41 22 53.42 25.90 10.18 2.60 3.34 1.34 0.00 0.003.22 23 52.98 25.69 10.09 2.58 3.31 1.33 0.00 0.00 4.01 24 53.59 25.9910.21 2.61 3.35 2.65 0.00 0.00 1.60 25 53.15 25.77 10.12 2.59 3.32 2.650.00 0.00 2.39 26 52.71 25.56 10.04 2.57 3.29 2.65 0.00 0.00 3.18 2752.28 25.35 9.96 2.55 3.27 2.63 0.00 0.00 3.97 28 52.86 25.63 10.07 2.583.30 3.97 0.00 0.00 1.59 29 52.43 25.43 9.99 2.56 3.28 3.94 0.00 0.002.38 30 52.00 25.21 9.90 2.54 3.25 3.94 0.00 0.00 3.16 31 51.57 25.019.82 2.51 3.22 3.93 0.00 0.00 3.93

TABLE 10B Ta₂O₅ and Nb₂O₅ Examples Normalized Moles of Batch CompositionEx. V₂O₅ BaO ZnO MoO₃ TeO₂ Ta₂O₅ Al₂O₃ SiO₂ Nb₂O₅ 21 48.87% 21.84%20.81% 3.01% 3.48% 0.50% 0.00% 0.00% 1.50% 22 48.61% 21.73% 20.70% 3.00%3.46% 0.50% 0.00% 0.00% 2.00% 23 48.37% 21.62% 20.59% 2.98% 3.44% 0.50%0.00% 0.00% 2.50% 24 48.87% 21.84% 20.81% 3.01% 3.48% 1.00% 0.00% 0.00%1.00% 25 48.62% 21.73% 20.70% 3.00% 3.46% 1.00% 0.00% 0.00% 1.50% 2648.37% 21.62% 20.59% 2.98% 3.44% 1.00% 0.00% 0.00% 2.00% 27 48.12%21.51% 20.49% 2.96% 3.43% 1.00% 0.00% 0.00% 2.50% 28 48.62% 21.73%20.70% 3.00% 3.46% 1.50% 0.00% 0.00% 1.00% 29 48.37% 21.62% 20.59% 2.98%3.44% 1.50% 0.00% 0.00% 1.50% 30 48.12% 21.50% 20.49% 2.96% 3.43% 1.50%0.00% 0.00% 2.00% 31 47.87% 21.39% 20.38% 2.95% 3.41% 1.50% 0.00% 0.00%2.50%

TABLE 10C Ta₂O₅ and Nb₂O₅ Examples Test Results 13 mm 13 mm Slide Slidebutton - button - 350 C. - 375 C. - 375 C. 400 C. Ex. 15 min 15 min 20min Results 20 min Results 21 4.5 6.5 13.24 glass 15.21 glass 22 4.0 6.512.42 glass 14.50 glass 23 2.5 6.0 12.24 glass 14.55 glass 24 4.5 6.512.56 glass 14.47 glass 25 3.0 5.0 12.35 glass 14.16 glass 26 4.5 6.012.19 glass 14.88 glass 27 4.5 5.0 12.30 glass 14.48 glass 28 3.0 5.512.16 glass 14.34 glass 29 3.0 5.5 11.62 glass 14.07 glass 30 3.0 5.511.79 glass 14.20 glass 31 3.0 6.0 11.77 glass 13.96 glass

TABLE 10D Ta₂O₅ and Nb₂O₅ Examples Test Results Continued Example 13 mmbutton - 425 C. 20 min Result 21 16.07 Haze 22 15.86 Haze 23 16.08 lighthaze 24 14.79 Haze 25 15.99 Glass 26 16.40 light haze 27 16.15 lighthaze 28 15.33 Haze 29 15.55 Glass 30 15.71 light haze 31 14.57 Haze

In certain example embodiments, the use of Ta₂O₅ and/or Nb₂O₅ may helpreduce the crystallization of the frit material. As the percentage ofcontribution by such additives increases, the softening temperature(e.g., a temperature at which the frit material may flow) may alsoincrease. In certain example embodiments, such properties may bedesirable for a tip off seal in a VIG unit (e.g., sealing the vacuumhole in a VIG unit).

Frit materials used for tipping off a vacuum hole may have differentdesirable properties than frit materials for a perimeter seal for a VIGunit. For example, a frit material used in a tip off seal may becompletely or substantially exposed to IR and therefore may reach ahigher temperature than that of a perimeter seal. Conversely, theperimeter seal may have the glass absorb some percentage of the SWIRdirected at the frit of a perimeter seal (e.g., 10%-30% of the SWIR).Thus, an exemplary frit material (e.g., example 21) may be used for aperimeter seal while example 26 may be used for tip off seal.

As shown in Table 10D, the example frit compositions may provideincreased resistance, or greater tolerance, to crystallization. Theexample compositions shown in Tables 7-10 were done in an aluminacrucible. With such a crucible, a certain amount of Al₂O₃ and SiO₂ maybe “leached” from the crucible during the frit preparation process.Thus, while Al₂O₃ and SiO₂ may not be shown in the above tables 7-10,these additives (or others depending on the crucible type) may yet bepresent in the frit composition due to the leaching process from thecrucible. The leaching of Al₂O₃ and SiO₂ may be a result of melting orfiring the frit compositions at certain temperatures (e.g., 800 C.degrees C., 1000 degrees C., etc). Different firing temperatures and/ordifferent lengths of time of firing may affect the amount of materialleached from the crucible. The variation of Al₂O₃ and SiO₂ may changethe frit performance for sealing at 375 degrees C. and 400 degrees C.

In certain example embodiments, Al₂O₃ may be included in a flit materialat between 0% and 2% normalized moles by composition, or at a normalizedweight percentage between 0% and 1.2%, or more preferably about 0.8%.SiO₂ may be included at between 1 and 5% normalized mole by compositionand/or between about 0.5 and 2% by weight, and more preferably about1.2% by normalized weight. The inventor has determined that in certaininstances, having SiO₂ or Al₂O₃ in amount greater than about 2-5%,resulted in undesirable flow qualities of the fit composition. Inparticular, when bonding to an example glass substrate, in certaininstances, higher percentages of SiO₂ or Al₂O₃ (e.g., in excess of 2 or4%) resulted in concrete like qualities for the final frit composition.

Table 11 shows example results in a platinum crucible. Such a cruciblemay reduce or even prevent the leaching of excess additives during thefiring process of the frit material.

TABLE 11 Platinum Crucible - Normalized Moles (%) V₂O₅ BaO ZnO CuClSnCl₂ TeO₂ Ta₂O₅ Al₂O₃ SiO₂ Nb₂O₅ 44.56 21.96% 18.21% 1.42% 4.66% 3.88%0.47% 1.19% 2.73% 0.93% 44.25 21.81% 18.09% 1.41% 4.62% 3.85% 0.46%1.20% 3.38% 0.92% 43.95 21.66% 17.96% 1.40% 4.59% 3.83% 0.46% 1.19%4.05% 0.91% 44.38 21.87% 18.14% 1.41% 4.64% 3.86% 0.46% 1.60% 2.71%0.92% 44.08 21.72% 18.02% 1.40% 4.61% 3.84% 0.46% 1.59% 3.36% 0.92%43.78 21.57% 17.89% 1.39% 4.57% 3.81% 0.46% 1.58% 4.03% 0.91% 44.2021.78% 18.07% 1.41% 4.62% 3.85% 0.46% 1.99% 2.70% 0.92% 43.89 21.63%17.94% 1.40% 4.59% 3.82% 0.46% 1.99% 3.38% 0.91% 43.60 21.48% 17.82%1.39% 4.56% 3.80% 0.46% 1.98% 4.01% 0.91%

FIGS. 12A-12C are graphs summarizing flow characteristics of examplefrit materials according to certain example embodiments.

FIG. 12A shows that, at 375 degrees C., increasing Ta₂O₅ percentage maycause an increase in the initial softening temperature and resultingreduction in the flow (e.g., the diameter of the 13 mm button) for theexample fit material. In certain example embodiments, increasing Nb₂O₅percentage may provide less of a reduction in flow. As noted above, afrit (e.g., Ex. 21) with this composition may be used for a perimeterseal of a VIG unit.

FIG. 12B shows that, at 400 degrees C., Ex. 21 has improved flowcharacteristics. For example, with 1.0% Ta₂O₅, the frit flows well.

FIG. 12C shows, at 425 degrees C., Ex. 21 continuing to flow at highertemperatures, although, as shown above in Table 10D, the fritcomposition may become crystallized at such a temperature. However, Ex.26 may continue to have good flow and has only a slight crystallization.Accordingly, Ex. 26 may continue to flow at higher temperatures.

It will be appreciated by those skilled in the art that CTE adjustmentsmay be carried out on the overall frit material (e.g., the compound) forthe glass wetting and bonding properties of the frit to cooperate withan underlying substrate (e.g., a glass substrate). In certain exampleembodiments, CTE matching compounds may be added for these and/or otherpurposes.

It will be appreciated that one or more metal oxide, chloride, and/orfluoride additives may be used as additives in different embodiments ofthis invention. Furthermore, in certain example implementations, themetal oxide, chloride, and/or fluoride additives may be stoichiometricor sub-stoichiometric.

As used herein, the terms “on,” “supported by,” and the like should notbe interpreted to mean that two elements are directly adjacent to oneanother unless explicitly stated. In other words, a first layer may besaid to be “on” or “supported by” a second layer, even if there are oneor more layers there between.

While the invention has been described in connection with what ispresently considered to be the most practical and preferred embodiment,it is to be understood that the invention is not to be limited to thedisclosed embodiment, but on the contrary, is intended to cover variousmodifications and equivalent arrangements included within the spirit andscope of the appended claims.

What is claimed is:
 1. A vacuum insulated glass (VIG) unit, comprising:first and second substantially parallel, spaced apart glass substrates;an edge seal provided around a periphery of the first and secondsubstrates to form a hermetic seal therebetween and at least partiallydefining a gap between the first and second substrates, wherein the gapis provided at a pressure less than atmospheric, wherein the edge sealis formed from a frit material at least initially having a compositionincluding: (Ingredient) (Normalized Mole %) vanadium oxide ~45-50%,barium oxide ~20-23%, and zinc oxide ~19-21%; and wherein the fritcontains SnCl₂ in an amount no greater than 6%.


2. A vacuum insulated glass (VIG) window unit, comprising: first andsecond substantially parallel, spaced apart thermally tempered glasssubstrates; an edge seal provided around a periphery of the first andsecond thermally tempered glass substrates to form a hermetic sealtherebetween and at least partially defining a gap between the first andsecond thermally tempered glass substrates, wherein the gap of thevacuum insulated glass (VIG) window unit is provided at a pressure lessthan atmospheric, wherein the edge seal is formed from a frit materialat least initially having a composition consisting essentially of zincoxide and: (Ingredient) (Normalized Mole %) vanadium oxide  33-55%,barium xoide  15-35%, MoO₃   1-6%; TeO₂   1-10%; Ta₂O₅ ≧0.46%; Nb₂O₅0.5-6%; and wherein the materials with the three highest normalized mole% in the frit material are vanadium oxide, zinc oxide, and bariun oxide.


3. The VIG unit of claim 2, wherein the frit material has a meltingtemperature less than or equal to about 400 degrees C.